package j20251026;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {
    private ServerSocket serverSocket=null;
    public TcpEchoServer(int port) throws IOException {
        serverSocket=new ServerSocket(port);
    }
    public void start() throws IOException {
        ExecutorService executorService= Executors.newCachedThreadPool();
        while(true){
            Socket clientSocket=serverSocket.accept();
            executorService.submit(()->{
                processConnection(clientSocket);
            });
        }
    }

    private void processConnection(Socket clientSocket) {
        System.out.printf("[%s:%d]服务器启动！\n",clientSocket.getInetAddress(),
                clientSocket.getPort());
        try(InputStream inputStream=clientSocket.getInputStream();
            OutputStream outputStream=clientSocket.getOutputStream()){
            Scanner  scanner=new Scanner(inputStream);
            PrintWriter  printWriter=new PrintWriter(outputStream);
            while (true){
                if(!scanner.hasNext()){
                    System.out.printf("[%s:%d]服务器关闭！\n",clientSocket.getInetAddress(),
                            clientSocket.getPort());
                    break;
                }
                //1.接收请求并解析
                String request=scanner.next();
                //2.根据请求，计算响应
                String response=process(request);
                //3.将响应传给客户端
                printWriter.println(response);
                printWriter.flush();
                //4.打印一个日志
                System.out.printf("[%s:%d] req:%s resp:%s\n",clientSocket.getInetAddress(),
                        clientSocket.getPort(),request,response);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }finally {
            try {
                clientSocket.close();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server=new TcpEchoServer(9090);
        server.start();
    }
}
